The Boating Forum - Installing cover snaps by drilling ?

I installed console cover snaps by drilling holes and then screwing in snaps. Upon doing this while I was screwing in the snaps I noticed the gel coat cracking and spidering around the hole, is this normal or should I have drilled a biger hole. I do not know how much bigger I could have drilled and still gotten a purchase with the screw. Tell me how it's done? The Hun

this is normal IF you dont countersink the holes first, before you drive in the snaps. Purchase a $2 countersink bit at your hardware store and just slightly countersink the holes first and you will avoid the gelcoat cracking!

I use a slightly larger size bit and switch the drill to reverse to score the hole first...Also if the gel is cracking after you've drilled it and while you are screwing it in, yes, the hole is undersized a bit. As an alternate you can use stainless pop rivets in lieu of screws

thehun - 12/16/2008 7:03 AM

I installed* console cover snaps by drilling holes and then screwing in snaps. Upon doing this while I was screwing in the snaps I noticed the gel coat cracking and spidering around the hole, is this normal or should I have drilled a biger hole. I do not know how much bigger I could have drilled and still gotten a purchase with the screw. Tell me how it's done? The Hun


I had the same problem. :(

You should countersink the holes, but you also need to drill them larger than you would think. I suspect you could drill just through the gell coat with a drill large enough to clear the screw, they use a smaller bit for the remainder of the hole.

This is where a caliper comes in handy. Drill a small ~1/8" pilot hole firstand then use a large bit at least the size of the threads out-to-out to cut backthe gel coat. The problem w/ using a countersink is that the CS is usually a steeper angle(~45*) and will remove more of the substrate, reducing the holding power of the screw. Drill the final hole w/ a bit "slightly" bigger(loose fit in the caliper) than the shank of the screw. Final step, pre-cut all the threads w/ a sacrificial screw that matches the snap screw(it may take a few). A lubricant,like soap, will make the threading easier.

They make chanfer bits for a drill. Drill the hole needed and before you install the screw you chanfer the edge and it makes it slightly wider. If the hole is too small for the screw it will always spider crack.

Everything everybody else already said but also "butter up" the threads of the screws with a dab of 5200 and your are set. You are right in that the countersinking and the fact that the hole needs to be pretty close to the size of the screw, the holding power is severely compromised. A dab of 5200 makes up for it perfectly........

.